1. Field of the Invention
This invention relates to the dyeing of textiles and, more particularly, to a method, an apparatus, and related dye compositions for dyeing textiles which operates at atmospheric pressure, is open to the atmosphere, and does not require the steaming of the textile to set or fix the dye to the textile. Specifically, this invention is a complete low temperature textile dyeing method which achieves a more complete and even dyeing of the textile in a shorter period of time using a dye composition capable of withstanding high temperatures without boiling or degrading
2. Prior Art
Conventional methods and apparatuses for dyeing textiles require the steaming of the textile to set or fix the dye to the textile after the dye has been applied to the textile. For example, the typical textile dyeing method and apparatus involves the application of a dye to the pile surface of the textile, fixing the dye onto the textile pile by steaming and then subjecting the textile to various other finishing procedures prior to drying the textile. The use of a steam fixator generally entails the use of a pressure vessel and/or other high pressure equipment. Further, because steaming generally takes place within the dyeing apparatus, steam can dilute the final color of the dye and, as it condenses into water, can dilute the actual dye composition itself. Because of these disadvantages it would be preferable to have a dyeing apparatus and method which does not require the use of steam. Various steam-based apparatuses and methods are known and discussed below.
The patent assigned to Vepa AG, U.S. Pat. No. 4,101,270, discloses a conventional method for dyeing textile which includes the steps of advancing a continuous textile web through a preshrinking station, moistening the textile web, dyeing the textile web using applicator rolls and/or dye applicators, and then fixing the dye onto the textile web by passage through, for example, a chamber containing steam. This basic method generally forms the base for the other prior art textile dyeing systems and is well known in the art as an example of the use of a steam fixator. Likewise, the patent to Fleissner, U.S. Pat. No. 4,771,497, discloses a process for the continuous treatment of a textile web material involving the application of a dye to the pile surface of the textile and then initiating the dye fixation onto the pile surface by steaming. Many of the prior art patents such as the two disclosed above involve such a steam fixation process and are distinguishable from each other by various additional, optional processes added onto this base dyeing technique.
The patent to von der Eltz et al., U.S. Pat. No. 3,986,831, discloses and claims a high temperature, high pressure batch process for dyeing materials which incorporates a sealed pressure vessel and high-pressure steam fixation. The '831 apparatus and method operate in an essentially air-free environment. Further, the dye fixation disclosed in the '831 patent occurs at a temperature over about 125.degree. C., creating the need for significant energy input. Likewise, the patent to Blount, U.S. Pat. No. 3,418,065, also discloses and claims a high temperature, high pressure batch process which also is carried out in a sealed pressure chamber not open to the atmosphere and which incorporates a steam fixation step. On the contrary, the present invention is open to the atmosphere and does not involve the use of steam or steam fixation. The present process is a continuous process which is carried out on a continuous-running apparatus. Further, the entire process of the present invention can occur at a temperatures below about 115.degree. C., and specifically below 100.degree. C., significantly reducing the energy costs and the apparatus costs.
The patent to Walter, U.S. Pat. No. 2,387,200, also discloses and claims a method for dyeing material which is carried out in a sealed chamber, namely a closed chamber incorporating compressed air and saturated steam. The '200 method is carried out at a temperature substantially above 100.degree. C. and under pressure. Therefore, the '200 method incorporates by its nature a steam fixation step as when the material emerges from the water-based dye bath which is heated substantially above 100.degree. C., the material encounters compressed air and saturated steam under pressure, which is the equivalent of a steam fixation step. The present invention does not comprise a closed or sealed chamber, but is open to the atmosphere, and does not use steam, thus eliminating the steam fixation step which can cause uneven dyeing and running of the dye. Further, the use of an open chamber and lower temperatures allows the present invention to be much more economical in terms of energy costs and apparatus material costs.
The disadvantages of such prior art textile dyeing methods and apparatuses which incorporate steam fixation components is the necessity for the steam fixation step and high pressures. Steam fixation has several disadvantages including the need for a tremendous amount of energy required to heat the steam, dilution of the dye as the steam condenses into water and mixes with the dye, and the cost of the equipment, both in material and time, needed to have a steam fixation step in the textile dyeing process. A further disadvantage is that a textile dyeing process including a steam fixation step is uneconomical to operate when dyeing small batches of textile.
Various other methods, apparatuses and compositions for dyeing textiles have been developed over the years, both at high temperatures, that is 100.degree. C. and above, and at low temperatures, that is below 100.degree. C., at atmospheric pressure and at high pressures, that is above atmospheric pressure, and using dye compositions using polyhydric alcohols, such as glycerol. The most relevant of these methods, apparatuses and compositions are discussed below. With regard to the specific methods and apparatuses, the prior art does not disclose the particular steps or features of this invention which allow a more complete textile dyeing in significantly shorter periods of time, thus reducing energy costs and dye composition costs while increasing the quantity of textile dyed per unit of time.
U.S. Pat. No. 2,461,612 to Olpin et al. discloses a method for dyeing solid articles, such as sheets, rods, and blocks, made of polymerized diallyl phthalate synthetic resins. Dyeing fabrics is not disclosed. The dye composition includes dye, an acid, at least 50% by weight of a polyhydric alcohol such as glycol or glycerol, and, optionally, water. The dye-bath has a claimed temperature from 130.degree. C. to 180.degree. C. This reference discloses that, under ordinary pressure, solutions of dyes in glycerol only can be employed at 140.degree. C. to 180.degree. C. and in an autoclave, under pressure, solutions of dyes in a mixture of glycerol and water can be employed at about 150.degree. C.
U.S. Pat. No. 2,882,119 to Laucius et al. discloses a method of dyeing polyester fabric comprising passing the fabric through a non-aqueous dye-bath including disperse anthraquinone dye, a strong acid, and an alkylene glycol. The bath is maintained at a temperature within the range of 130.degree. C. to 200.degree. C. during dyeing. This patent does not disclose details of the dyeing apparatus and does not disclose whether the apparatus is open or closed, or whether the dyeing is performed under pressure. However, the use of glycol, a known pollutant, is a disadvantage.
U.S. Pat. No. 3,461,467 to Duncan discloses a boil control apparatus for use with an atmospheric dye kettle for dyeing fabrics. The apparatus is open to the atmosphere and specifically is used to prevent boil over of a dye kettle, which uses steam to heat the liquid by injecting steam into the liquid.
U.S. Pat. No. 3,558,260 to Hermes discloses a method for dyeing textiles comprising a mixture of wool and a polyester in a closed aqueous dye-bath comprising benzyl alcohol or a benzyl alcohol/propylene carbonate or dipropylene carbonate mixture maintained at 75.degree. C. to 100.degree. C. The principle of this apparatus is to have a dye liquor flow codirectional with the textile movement, requiring means to create a dye liquor flow, rather than the use of a typical generally static dye bath. U.S. Pat. No. 4,047,889 to Hermes discloses a non-aqueous method for dyeing fabric, preferably polyester, in a high temperature non-aqueous dye-bath wherein the solvent is a high boiling solvent, preferably ethylene glycol. The fabric is dyed at over 300.degree. C. and then washed in a low boiling liquid, preferably methanol. This patent also discloses recycling of the dye, removal of dye from the fabric, and washing of the dyed fabric. The claimed process employs complete recycling of materials, rather than the use of environmentally-friendly materials.
U.S. Pat. No. 4,082,502 to von der Eltz et al. discloses a process for dyeing textiles wherein the textiles are passed through a dye-bath in a pressurized sealed container at temperatures substantially greater than 100.degree. C. in which saturated or superheated steam is used. The dye solution is pre-mixed and heated before entering the bath chamber. The textile is preheated and deaerated by exposure to steam prior to dyeing. Post-dyeing heat treatment is used to fix the dye.
U.K. Patent No. 1241820 discloses a process for dyeing pile carpets in which the fabric is sprayed with a dye composition from nozzles and then heated in a steam chamber. The dye composition can include a boiling point elevation means such as glycol so that dyeing can be done at temperatures greater than 100.degree. C. However, this patent teaches the operation of this process in a steam setting chamber.
U.K. Patent Application No. 2 063 943 discloses a process for dyeing fabric wherein the fabric passes through a dye-bath contained in a pressurized vessel which comprises a high pressure steamer body. The dye-bath is maintained at temperatures greater than 100.degree. C. The dye is mixed and preheated in a vessel separate from the bath chamber. U.K. Patent Application No. 2 125 449 discloses a process for dyeing heat shrinkable polyester knit fabric wherein the fabric is heated before dyeing to shrink and set the fabric. The fabric is dyed under pressure in a loop steamer. In effect, this application discloses a preshrinker.
With regard to the specific dye compositions, while the prior art does disclose glycerin or glycerol in dye compositions, a trihydric alcohol-based category of dye compositions which can be formulated for use in multiple dyeing applications is not disclosed. The specific dye composition formulations allow a more complete textile dyeing using less of the dye composition, thus reducing dye composition costs. For example, an excess amount of dye is carried with the textile from the dye bath and is washed off in the wash box or washing step. This results both in wasted dye and in a more polluted wash stream which must be disposed of in some manner. The present invention significantly reduces the amount of excess dye carried with the textile from the dye bath, resulting in a lower overall dye usage and much cleaner wash streams. Further, the specific dye composition formulations dye the textiles more quickly, thus reducing dyeing time and energy costs. The specific dye compositions also are environmentally friendly and recyclable.
U.S. Pat. No. 1,660,167 to Kem discloses a method of printing on and dyeing textiles using a composition comprising a basic dye, lactic acid, water, a glycerin solution comprising glycerin, formic acid and benzoic acid, and a tannic acid solution comprising tannic acid and lactic acid, mixed with a starch paste and acetic acid. This composition is for use in cold or ordinary temperature applications, and does not require steaming of the fabric, but does require a subsequent fixing of the dye on the fabric by a firming or fixing bath, such as an antimony salt.
U.S. Pat. No. 2,827,357 to Hannay et al. discloses an alkali vat dye based on molten metal bath dyeing. This particular dye has an increased amount of alkali and is not of the polyhydric alcohol class.
U.S. Pat. No. 3,811,836 to d'Albignac et al. discloses a general category of anionic acid dyes which comprises a polyol and a sulphonic or carboxylic acid containing dyestuff which is in the form of a free acid. Synthetic textiles are dyed in 10-120 seconds at a temperature from 90.degree. to 160.degree. C. using this free acid containing dyestuff. Washing in a low boiling point solvent mixture, such as acetone, then is required.
U.S. Pat. No. 3,819,324 to Bino discloses a fugitive dyeing process for polyesters wherein glycerol is used as a solvent. The invention is for distinguishing between two or more differently colorable textiles by subjecting the textiles to an ester, and then treating with an aqueous or alcoholic solution of an acid dye to bring out the color contrast. The color, being fugitive, can be easily scoured from the textile, so the textile can be redyed.
U.S. Pat. No. 3,920,385 to Bohny et al. discloses a process for dyeing leather by contacting the leather with a composition comprising water, dye, an organic solvent such as glycerol, and various additives. The dye-bath temperature ranges from 25.degree. C. to 80.degree. C.
U.S. Pat. No. 3,920,386 to Beyer et al. discloses a process for dyeing cellulose fibers at room temperature comprising contacting the fibers with an aqueous dye-bath including an azo dyestuff, a coupling component, a non-diazotized primary aromatic amine in a solvent such as glycerin, and various other additives. The dye-bath is at room temperature. The fibers are subjected to a post-dyeing heat treatment. This process discloses an alternative dyeing process for cellulose fiber containing fibers.
U.S. Pat. No. 4,076,496 to Hamano discloses a method of dyeing synthetic resin articles such as extruded articles of acrylic resin, polyurethane resin, polyamide resin, polycarbonate resin, acrylonitrile-butadiene-styrene copolymer resin, and polyvinylchloride resin without softening the resin. The method includes dipping the article in a heated solution comprising dye, a polyacid, a polyhydric alcohol such as glycerol, but preferably a dihydric alcohol, and water. There is no fixing step after the dipping. The dye-bath temperatures disclosed are no greater than 90.degree. C. and dyeing of fabric is not disclosed. The polyhydric alcohol is used as a solvent for the acid and is present in the dye solution from 5 to 50% by weight.
U.S. Pat. No. 4,150,947 to Lang et al. discloses concentrated dispersions of water-soluble basic dyestuffs comprising 10 to 80% by weight of a dyestuff free of inorganic salts, 90 to 20% by weight of a dispersion medium comprising a polyhydric alcohol such as glycerol in which the dyestuff is insoluble, and up to 20% by weight water. The boiling point of the dispersion is not below 80.degree. C. and preferably not below 100.degree. C., and has a viscosity of 100 to about 250 cp at 20.degree. C. There is no disclosure of a method for using the dye to color fabric.
U.S. Pat. No. 4,218,218 to Daubach et al. discloses aqueous dye dispersions comprising a dye, a particular surfactant, a mixture of water and a water-retaining agent such as glycerol, and various additives. The glycerol is added to prevent drying-up and encrusting of the fluid formulation. The dispersions are useful in dyeing packages, but no details on the dyeing process are provided.
U.S. Pat. No. 4,786,288 to Handa et al. discloses a process for ink jet dyeing a polymer substrate to produce sharp patterns with a composition comprising glycerol as a carrier. The dye is fixed to the substrate with a post-dyeing steam treatment. The fabric is pretreated with a soluble Group IA or IIA salt and a cationic compounds, and then treated with a copolyester. This is a specific composition which will resist running during application, unlike the common textile dye.
U.S. Pat. No. 5,104,415 to Koci discloses a method for dyeing synthetic textiles wherein glycerol is used as a dye promoter. The formulation comprises a generally water-insoluble dye, a sulfated polyadduct, water, a betain monohydrate, and an anionic dispersant of a particular formula. The dye-bath temperature is 10.degree. to 60.degree. C. This formulation is an alternative dye for printing on synthetic materials. Likewise, U.S. Pat. No. 5,240,465 to Palacin discloses a textile dyeing method wherein glycerin is used as a solubilizing agent. The dye-bath temperatures are between 20.degree. C. and 100.degree. C. This is a process for dyeing cellulosic containing textiles with reactive dyes, using sulphonated ethers or sulphones, and then fixing the dye using an alkali.
This inventor has developed a method an apparatus for dyeing textile which, in its best mode for dyeing carpet, is open to the atmosphere and operates at atmospheric pressure, and at temperatures of 100.degree. C. or greater. The method is covered under U.S. Pat. No. 5,199,126, and the apparatus is covered under U.S. Pat. No. 5,201,959. The development of the open-to-the atmosphere process and apparatus also allows for the dyeing of materials at significantly lower energy costs and with a higher degree of safety. Less energy is necessary as there are no materials to be superheated and no pressure needs to be created. Materials costs are reduced as vessels open to the atmosphere typically do not need the reinforcing required for a pressure vessel. Lastly, pressure operations typically inherently are more dangerous than an equivalent atmospheric operation.
The '126 method and '959 apparatus comprise a novel dye bath applicator which effects the textile dyeing and fixing step by utilizing a high temperature dye mixture, the boiling point of which is higher than the boiling point of water. The apparatus is open to the atmosphere and does not constitute a pressure vessel in the sense disclosed in prior art dyeing apparatuses. By eliminating the need for pressure vessel-type couplings and materials, the apparatus is both much less costly and safer to operate. The apparatus also generally comprises a heated mix tank which effects the heating step of the dye and chemicals, a heat exchanger which effects the step of heating the dye prior to the dye entering the applicator, and wash boxes with overflows which effect the step of neutralizing the pH of the textile and washing the textile before the textile enters the drying stage. No open steam lines are used to heat any dye solutions or chemicals, or to heat any components of the apparatus, including the heated mix tank, used in this invention. Although the '126 method and '959 apparatus originally were developed for use in dyeing carpet, they can be used for dyeing other textiles and at temperatures below 100.degree. C. with excellent results. The present invention was developed as an alternative both to high temperature dyeing and to dyeing carpet by creating a method, apparatus and composition which is equally useful at low temperature and for other textiles.